Lubricating emulsion



Patented Apr. 30,

UNITED STATES 'LUBRICATIN G EMULSION Robert C. Williams, Columbus, Ohio, assignor to The Ironsides Company, Columbus, Ohio, a

corporation of Ohio No Drawing.

Application October 23, 1935, Se-

rial No. 46,447. Renewed October 31, 1939 4 Claims.

The present invention relates to an improved lubricating emulsion of the type in which oleaginous compounds in minor percentages are admixed in water, and the primary object of the invention resides in the'provision of'an economical yet efiicient lubricant which may be effectively employed in the lubrication of industrial machinery and often with better results than can be obtained with commonly accepted lubricants.

The lubrication of various types of gears, journals and bearings in industrial machinery is ordinarily accomplished with the use of oils or greases which are either free from water or contain-water in minor percentages in the form of the water-in-oil type of emulsion. Within the last few years, considerable emphasis has been placed upon the investigation and development of so-called extreme pressure lubricants. For instance, it has been found that refined straight petroleum oils do not satisfactorily lubricate many gear sets and power transmission machinery, such as are commonly employed in many modern metal working machines. It has" been shown that the viscosity of an oil in itself has little to do with the load-carrying" capacity of the oil. In other words, the operation of a hypoid gear set under severe service conditions generally results in badly scored gears even with the most highly refined oil of appropriate viscosity. Other conventional physical properties,

such as fire and flash point and specific gravity have little in themselves to do with the film strength of the oil under the conditions as described above. Therefore, the use of so-called addition agents in petroleum oils is a common expedient to render them effective under severe pressure conditions.

The chemical nature of addition agents is generally agreed upon to be the determining factor in compounding a straight petroleum oil to make it effective as an extreme pressure lubricant. Thus, the petroleum oil may be combined with sulphur or chlorine, in some form to attain the desired results. Lead soaps may be added, sulphurized polymers obtained from the de-gum-- ming treatment of highly cracked gasolines, and quite a number of other definiteand indefinite chemical combinations involving sulphur, chlorine or phosphorus are now available .on the market as extreme pressure addition agents.

' There is a trend to distinguish among extreme bricants for operations, such as cutting, drawin or stamping, which contain water in major proportions and are prepared as "oil-in-water emulsions, but many of these emulsions, because of their composition, are not suitablefor general lubricating purposes.

The present invention relates to the use of a novel and improved oil-in-water type of emulsion which of itself is highly suitable for the lubrication of gears and bearings where any effects the water itself may have are not objectionable, and consists in the provision of an emulsion where water in the continuous phase is combined or admixed with minor percentages of body supplying oleaginous compounds.

As an example of the emulsion comprising the present invention, '1 have found that a mixture composed of 5% of tallow dispersed in an aqueous solution containing 1% of potash soap may be used. This emulsion was found to prevent scoring of the test pieces of the Timken lubricant testing machine with a load of 20 pounds on the lever arm, whereas a well known motor lubricating oil of accepted high quality did not prevent scoring under equivalent time conditions with only 5 pounds on the lever arm. In both cases, the machine was operated at a rubbing speed of 400 feet per minute.

' In another variation of the present invention, an aqueous solution comprising 6% rapeseed oilpotash soap and the remainder water prevented scoring, under identical test conditions, with the lever arm weighted to the extent of 10 pounds. Under this test, the rapeseed oil-fatty acids, produced by hydrolysis of the soap, were dispersed in the solution as the "oil, and formed the lubricating film. Emulsions of, waxes and waxlike materials. have also successfully provided I lubricating films having film strengths or frictional resistances superior to those obtained with the use of straight petroleum oil, as disclosed'in my prior United States Patent No. 1,948,194, is sued February 20, 1934. As an example of a wax emulsion which may be used in carrying out the present invention, the following composition has been found to be efiective:

Per cent Potash soap made from a 42 titre fat 1.8 Candelilla wax 3.2 Water 95.0

From the above, it will be noted that the "oilin-water emulsions comprising the present invention contain water in major proportion, that is, of the order of 90% or higher, and will have mild extreme pressure properties, as distinguished from refined straight lubricating oils which are not classed as extreme pressure lubricants in the absence of extreme pressure addition agents therein.

As an example of a blended tallow and wax emulsion, the following composition wasemployed:

Another form of the present invention consists in the preparation of a mixture, to which water is subsequently added by the user of the final lubricant, comprising Per cent Water 50.0 Rapeseed oil-potash soap 40.0 Light paraffin oil 10.0

Practical useof my improved emulsions may be made to the lubrication of roll necks in metal rolling operations where conventional practice is to place a supply of plastic grease or a solid block of grease on the necks and allowing water to flow over the latter so that the neck is both cooled and lubricated. In such practice, the spent lubricant is washed away and lost. With the emulsions comprising the present invention, the cooling and lubrication may be accomplished with efliciency and without appreciable loss by recirculating the emulsion. The heat absorbing capacity of water is well known owing to its high specific heat compared with that for pctroleum oils. In addition, cooling effected by the evaporation of water proves advantageous in certain cases. The present lubricants are particularly efiective in the cooling and lubrication of non-metallic composition bearings which are now being widely substituted for conventional metallic bearings.

From the foregoing, it will be readily seen that lubricants containing water in major proportion and as a continuous phase, with minor percentages with such dispersed agents as tallow, soft soap and/or wax, can advantageously replace conventional oils and grease lubricants from the standpoint of both cost and effectiveness.

Aii'other characteristic of the emulsion made in accordance with the present invention is its low free alkali content, which is usually not in excess of pH 12. If desired, glycerin or other antifreeze agents may be added to any of the above compositions to protect the latter when employed under conditions of exposure to low or freezing temperatures.

What is claimed is:

1. An extreme pressure lubricant comprising an oil-in-water emulsion containing: water in excess of 90%, a small percentage of potash soap and a higher percentage of tallow and having a low free alkali content not substantially in excess of pH 12.

2. A lubricant comprising an oil-in-water emulsion and having mild extreme pressure properties, the water being present in the continuous phase to an extent in excess of 90% by weight, and having dispersed therein minor percentages of a saponifiable addition agent composed of potash soap and candelilla wax and having a low free alkali content not substantially in excess of pH 12.

3. An extreme pressure lubricant consisting of an emulsion containing at least 90% by weight of water, an oleaginous ingredient of about 2 to 5%, a potash soap from about 1% to 1.8%, the water being in continuous phase and the composition having a low free alkali content not substantially in excess of pH 12.

4. An extreme pressure lubricant for lubrication and cooling of gears and bearings carrying high loads consisting of an oil-in-water emulsion containing over 90% by weight of water, from 1% to 1.8% of potash soap, from 1.6% to 3.2% candelilla wax, the water being in continuous phase and the emulsion having a low free alkali content not substantially in excess of pH 12.

, ROBERT C. WILLIAMS. 

